Combining the use of two non-invasive instruments to confirm that a formula can improve skin luminance while respecting constitutive melanogenesis.

Abstract

Skin radiance products achieve perceivable benefits with different sort of mechanism of action. To use two non-invasive instrumental devices to evaluate the effectiveness of a cosmetic formula designed to improve skin reflectance while respecting skin integrity. Subjects (N=43) aged 18-50 years old had healthy skin of phototype V-VI and Individual Typology Angle between -10° and -50°. The treatment was applied twice weekly for 4 weeks on a delineated area of the back, and an adjacent area was left untreated. Instrumental and clinical scoring assessments of treated and untreated skin were performed at baseline and Day 26. Between baseline and Day 26, reflectance (Delta L*) increased by 1.27 points and was considered as clinically relevant. Dermatologist clinical scoring of radiance significantly improved from 2.6 to 3.6 after 4 weeks of treatment and the Skin Color Chart Clarity level significantly decreased from a score of 15.5 to 14.3, representing a skin reflectance improvement. Conversely, the change between baseline and Day 26 in Mexameter Melanin Density was not clinically different for treated skin versus untreated skin (difference of 2.54). At Day 26, changes from baseline for Mexameter Melanin Density and Delta L* parameters appeared to be uncorrelated (r=-0.036). This combination of two non-invasive devices can be useful to confirm that a product can modulate skin reflectance without modifying constitutive pigmentation. The formula tested in this study did not interfere with constitutive melanogenesis.